Message ID | 20240814-lpm-constraints-firmware-msp-v10-0-bee4314bbdc8@baylibre.com (mailing list archive) |
---|---|
Headers | show |
Series | firmware: ti_sci: Introduce system suspend support | expand |
Hello all, On Aug 14, 2024 at 08:39:27 -0700, Kevin Hilman wrote: > Abstract > ******** > > This series introduces necessary ti_sci driver functionality to support > various Suspend-to-RAM modes on TI AM62 family of devices. These Low > Power Modes include Deep Sleep and MCU Only as described in section > "6.2.4 Power Modes" of the AM62P Technical Reference Manual [0]. > > Summary > ******* > > This series is a restructuring and rebase of the patch series by > Dave Gerlach [1] and Dhruva Gole [2]. It applies on top of Linux > 6.11-rc1. > > The kernel triggers entry to Low Power Mode through the mem suspend > transition with the following: > > * At the bootloader stage, one is expected to package the TIFS stub > which then gets pulled into the Tightly coupled memory of the Device > Mgr (DM) R5 when it starts up. If using U-Boot, then it requires > tispl.bin to contain the TIFS stub. Refer to documentation in upstream > u-boot[3] for further details. The supported firmware version is from > TI Processor SDK >= 10.00 ie. tag 10.00.04 from ti-linux-firmware [4]. > > * Use a TF-A binary that supports PSCI_SYSTEM_SUSPEND call. This causes > system to use PSCI system suspend as last step of mem sleep. > > * We add support for the TISCI_MSG_QUERY_FW_CAPS message, used to retrieve > the firmware capabilities of the currently running system firmware [6]. > Sysfw version >= 10.00.04 support LPM_DM_MANAGED capability, where > Device Mgr firmware now manages which low power mode is chosen. Going > forward, this is the default configuration supported for TI AM62 family > of devices. The state chosen by the DM can be influenced by sending > constraints using the new LPM constraint APIs. (Patch 1) > > * The firmware requires that the OS sends a TISCI_MSG_PREPARE_SLEEP > message in order to provide details about suspend. The ti_sci driver > must send this message to firmware with the above information > included, which it does during the driver suspend handler when > PM_MEM_SUSPEND is the determined state being entered. The mode being > sent depends on whether firmware capabilities have support for > LPM_DM_MANAGED feature. Legacy firmware or those supporting other > modes can extend the mode selection logic as needed. (Patch 2) > > * We also add the remaining TISCI Low Power Mode messages required for > inquiring wake reason and managing LPM constraints as part of a new PM > ops. These messages are part of the TISCI PM Low Power Mode API [5]. > (Patch 3) > > * Finally if any CPUs have PM QoS resume latency constraints set, we > aggregate these and set the TISCI system-wide latency constraint. > (Patch 4) > > Testing > ******* > > This series can for example be tested with a am62a-lp-sk board. > > For am62a-lp-sk all usb nodes have to be disabled at the moment (usbss0, > usb0, usbss1 and usb1). There is currently an issue with USB Link Power > Management and turning off the USB device which is being worked on. > > Once booted suspend/resume can be tested with rtcwake: > $ rtcwake -m mem -s 10 -d /dev/rtc0 > > Make sure /dev/rtc0 corresponds to rtc-ti-k3: > $ dmesg | grep rtc-ti-k3 > rtc-ti-k3 2b1f0000.rtc: registered as rtc0 Additionally, one can refer to this guide for more details: https://software-dl.ti.com/processor-sdk-linux/esd/AM62X/latest/exports/docs/linux/Foundational_Components/Power_Management/pm_low_power_modes.html For the series, Tested-by: Dhruva Gole <d-gole@ti.com> Logs: https://gist.github.com/DhruvaG2000/658d0d4683b13ab41025df19a8eafc2f Tree with all the patches applied: https://github.com/DhruvaG2000/v-linux/tree/lpm-k3-next